黄土区不同类型土壤微生物量碳、氮和可溶性有机碳、氮的含量及其关系

研究了黄土高原南部地区不同土壤类型及不同利用方式下土壤微生物摄碳、氮和可溶性有机碳、氮的含量。结果表明：不同土地利用方式下，土壤微生物量碳、氮和可溶性有机碳、氮含量均为林地〉农田，其中林地枯枝落叶层〉林地O～20cm土层。农田土壤微生物量碳、氮的含量均为红油土〉黑垆土〉淋溶褐土；农田土壤中可溶性有机碳含量为淋溶褐土〉红油土〉黑垆土，而可溶性有机氮含量则为黑垆土〉红油土〉淋溶褐土。方差分析表明，不同土壤类型土壤微生物量氮含量之间的差异达显著水平，而不同土壤类型间土壤微生物量碳、可溶性有机碳、氯含量之间的差异未达显著水平。土壤微生物量碳、氮占土壤有机碳和全氮的比例明显高于可溶性有机碳、氮占土壤有机碳和全氮的比例。相关分析发现，土壤微生物量碳与可溶性有机碳之间以及土壤微生物量氮与可溶性有机氮之间的相关性达显著或极显著水平，说明土壤微生物量碳、氮和土壤可溶性有机碳、氮之间有密切联系。

Contents of Soil Microbial Biomass C, N and K2SO4-extractable Organic C,N and Their Relations in Different Soil Types on Loess Plateau of China

This study was conducted to determine the contents of soil microbial biomass carbon(BC),and nitrogen(BN),K_2SO_4-extractable organic carbon(DOC),and nitrogen(SON) in three different soil types and under two different use patterns in the south part of Loess Plateau.The results showed that the contents of BC,BN,DOC and SON in the forest soils were higher than those in the arable soils;and the concentrations of these parameters in the forest litter were significantly higher than those in the 0~20 cm soil layers.Under the different agricultural cultivation,the concentrations of BC and BN in the anthrosols were higher than those in the isohumisols and the argosols.The concentration of DOC in the argosols was higher than that in the anthrosols and the isohumisols.The concentration of SON in the isohumisols was higher than that in the anthrosols and the argosols.Soil types had significant effect on the concentration of BN,but had no significant effect on the concentrations of BC,DOC and SON.The ratios of BC to soil organic C(BC/TC),and BN to soil total N(BN/TN) were significantlyhigher than the ratios of DOC to TC(DOC/TC),and SON to TN(SON/TN).There were significant positive correlations between BC,BN and DOC,SON,indicating the close relationships between BC,BN and DOC,SON.